Rain gutters are constructed to collect water and are installed at the edge (periphery) of the roof of most residential structures in order to direct the water away from the building and its immediate surroundings. A problem of such rain gutters is that they also collect leaves, pine straw, and other debris, which can clog the rain gutter or otherwise prevent the gutter from performing its intended functions. As a result, the rain gutter performs ineffectively or, in some situations, not at all. At that point, the rain gutter must be cleared of debris.
In order to prevent debris from entering the gutters and to eliminate the need to clear the gutters, various rain gutter covers have been provided. Such covers are installed above the open trough of the gutter. They are designed to prevent debris from entering the gutters while allowing water to flow into the gutter's trough.
Covers offered in the past utilize “surface tension” to direct water around a rounded nose portion of the cover into the gutter's trough, while debris is deflected overboard to the ground. Surface tension is the linking exhibited by water molecules that are attracted to one another by intermolecular forces. As a result, rain water collects due to surface tension and is drawn around the cover's nose into the gutter's trough. Examples of such gutter covers may be seen in U.S. Pat. Nos. 4,796,390, 4,497,146, and 4,404,775, which are incorporated herein by reference in their entirety for all purposes.
“Wettability” is a cover's ability to cause water on the cover to film or “sheet,” flowing in a manner resembling a uniform sheet of water. Wettability enhances the utility of surface tension so that water spreads out into a uniform sheet or film and is drawn around the cover's nose portion and into the gutter. Accordingly, covers have attempted to maximize wettability and surface tension properties so that rain flows into gutters in an improved manner.
Water adheres to a surface traversing its contour when the amount of rain water flowing is sufficient to maintain an unbroken (steady) stream. Only after an initial period of rain fall and only when rainfall rate is significant does there develop a sufficient film of water on the cover's surface to sustain continuous flow. As a result, effective gutter covers of the prior art have tended to have nose portions with a larger radius. The larger, more gentle turn generally requires a lower volume of water to achieve suitable wettability and flow than is the case with smaller radii.
While gutter covers having larger diameter nose portions may perform well, they pose certain objectionable considerations. For example, the gutter itself sometimes must be moved downward on the fascia of the house in order to allow sufficient space for the cover to be located between the gutter and the roof. In addition, the cover's upstream edge must generally be placed under the second or third course of shingles. Requiring relocation of the rain gutter is costly, while requiring placement higher on the roof than the first course of shingles may be aesthetically objectionable.
In addition, the color of large radius gutter covers generally needs to be matched with that of the roof shingles, thus requiring the provider to maintain a large inventory of different colors. Often, particularly where the roof pitch is shallow, the cover is installed on top of the second course of shingles using a butyl seal strip. While the seal-strip is effective in service, it can be difficult to remove and replace when or if the roof is reshingled. In addition, installation of those covers on other type of roofs, such as shake, tile, or slate, can be difficult or impossible.
In view of these considerations, attempts have been made to provide gutter covers with small radius nose portions. Because of the small radius, however, initial wetting of the lower water directing portion of the cover is more difficult to achieve. For example, at the initiation of rainfall and when the quantity of falling water is minimal, water may tend to accumulate in beads at the cover's nose. This water may then drip onto the gutter and run down its face instead of collecting into sheets and being drawn into the gutter as desired. Water dripping down the gutter's face (instead of into the trough) may cause what is known as “tiger striping.” Water dripping down the gutter's face may also carry dirt and debris with it, a portion of which is deposited on the gutter's face. These undesired results can cause unsightly stains to appear on the face of the gutter.
An equally vexing problem associated with the dripping that occurs in minimal rainfall conditions is the tendency for icicles to form in cold weather. Gathering ice is undesirable in that it may seal off the slot through which water from the cover enters the gutter. Moreover, icicles over entrance ways create a danger to people standing or passing below them.
In most situations, as rain water accumulates on the roof of a structure, it begins to flow toward gutters at increasing rates. In order for a rain gutter cover to be able to direct rain water into a rain gutter, it must be constructed in a manner that is capable of handling these increasing rates. Otherwise, the rain water flowing over the cover will fail to adhere to the nose contour and will be jettisoned overboard to the ground.